Randomely, my portfolio items started sorting alphabetically by title as opposed to by date posted, like they had always been. What could cause this, and how do I reverse it?

Also, after making a few changes in portfolio location, and then deciding to go back to keeping it on the front page, it will no longer display. When the portfolio is set to display on it’s own page, “portfolio,” it works. When it’s set to display on the “Home” page, nothing happens.